The hydrothermal vents that line the mid-ocean ridges are a major source of iron for the creatures living in the sea. Humans are not the only ones who suffer when iron becomes scarce; creatures such as phytoplankton are known to grow listless in waters low in iron, even if they are drifting around in an environment rich in many other types of nutrients.

Earlier, scientists assumed that the iron exuded from hydrothermal vents immediately formed mineralized particles as soon as it came in contact with the salty water – a form of iron that is hard to utilize for living creatures.

New research has however unveiled that some of the iron spewed out from these vents actually remain in a form that is easy to absorb for oceanic beings. According to researcher Brandy Toner, a surprising interaction between iron and carbon in hydrothermal vents serves to stop the corrosion.

“Iron doesn’t behave as we had expected in hydrothermal plumes. Part of the iron from the hydrothermal fluid sticks to particulate organic matter and seems to be protected from oxidation processes,” Toner explains.

The research was carried out on hydrothermal vent particles collected by the team from the Tica vent in the Eastern Pacific Rise. With the help of the Advanced Light Source synchrotron at the Lawrence Berkeley National Laboratory, Toner was able to analyze the particles using focused X-ray beams.

Iron is a key player in this newly discovered process in the ocean, but the exact mechanisms remains unknown.

“So the question becomes, what are those organic compounds? Are they organic compounds like in oils and tars or is it actually the stuff of life?”, says Chris German, co-author of the paper. “Brandy’s work doesn’t mean that these [carbon-iron] complexes are definitely alive. But, this is a possible smoking gun. This paper opens up a whole new line of research and asks a new set of questions that people didn’t know they should be worrying about until now. A bit of work on a tiny nanometer scale can force you to ask questions of global significance.

Perhaps hydrothermal venting, a process traditionally believed to be a completely inorganic process, actually is a part of the organic carbon cycle on our planet.

The paper “Preservation of iron (II) by carbon-rich matrices in a hydrothermal plume” by Brandy Toner and her colleagues[1] has been published in Nature Geoscience[2].